Ambient air quality of two metropolitan cities of Pakistan and its health implications

Abstract

The present study reports findings on TSP loading in the ambient air of two major cities in Pakistan – Karachi and Islamabad. Data for TSP were collected at one site in Karachi and two in Islamabad between 10 December 1998 and 08 January 1999. This article reports one of the highest TSP loadings recorded so far in any megacity of the world. During the study period, average daily TSP concentrations at the Karachi site ranged from 627 to 938 μg m −3 with a mean of 668 μg m −3. On four occasions TSP concentrations were >1000 μg m −3 (range 1031–1736 μg m −3). At the Islamabad sampling site in close proximity to the city's industrial sector, daily TSP concentrations varied in the range of 428–998 μg m −3 (mean 691 μg m −3). Even at a relatively remote site of the city (Saidpur), TSP loading was high (range 145–448 μg m −3; mean 275 μg m −3). By virtue of the WHO definition, the 24-h average TSP concentrations in a busy commercial site in Karachi and in the vicinity of an industrial sector in Islamabad were in “exceedance” by a factor of 4–8. At Saidpur, the remote site, the 24-h average TSP loading exceeded the WHO guideline of 120 μg m −3 by a factor of 1.2–3.7.